I recently purchased a Celviano AP-650. I have just noticed that when I play certain sounds (like GM Tinklebel, no 113 on GM tones), the chord accompaniment is off by one full note. If a play a C chord with my left hand, the actual chord played is a G. This does not happen with all sounds. I have reset the piano to its factory settings twice and the problem still exists. Would appreciate some help on this matter. Thank you